ok. I wasn't sure what you are referring to. in mac land that's called screen sharing. yes, there are a number of ways to do this. the easiest is to use ichat. you just need to get a mobileme account (not free) or a google account (free) or aim account ( also free). then both you and your friend log into ichat and there is an option to ask the other party to share their screen.
there is also built in screen sharing but that's trickier to use and usually requires some router configuration. ichat can be set up in 5 minutes and does not require anything.
